Hot Water Heater Repair 

Hot water heater repair, like any other repair job, becomes much simpler if you understand how things work.

If you know what a certain part is suppose to do, and when its suppose to do it then its easy to check to see if its working like it should.

Basically, all residential duel element water heaters work the same and most parts are interchangeable.

Gas water heaters, traditionally very simple to troubleshoot and repair, have become a bit more complicated with sealed burners and safely switches, Not all gas water heater parts are interchangeable.

Working with gas or electricity can be dangerous. If you have any doubt about your abilities I recommend that you call your local plumber or repairman. Please read our disclaimer.

The hot water heater repair tutorials on this page are common to both gas and electric units.
Visit electric water heater repair for specific electric hot water heater problems.

Pressure Relief Valve

The temperature/pressure relief valve, also called prv or t&p valve, is the most important part of a water heater. If all other safety functions fail, the prv valve will keep the tank from exploding.

How can a water heater tank explode? Water expands an it is heated, extreme temperatures will create extreme pressure. If there is a system failure on the unit and the water continues to heat unchecked, the pressure will increase until the tank fails. It can be compared to a bomb exploding.

In case of a system failure the prv valve will open and release some of the hot water, which will reduce the pressure and keep you safe.





Water heater explosion

Why a prv valve would fail

Over a period of time, sediment, calcium deposits and rust can cause a prv valve to freeze up. This is another reason to flush and clean your tank on a regular basis.
The levers on prv valves are spring loaded. If its allowed to snap shut after its raised it could damage the valve.

Pressure relief valves are very reliable, however they should be checked regularly. At least once a year. Opening the valve will also help to flush away debris that may be building up in the valve.

When you are doing a hot water heater repair or check on a prv valve, it should be plumbed to the outside. Do not open the valve if it has not been plumbed. It will release lots of hot water fast.

This water heater relief valve page will show you how to check, troubleshoot or replace a relief valve.

Sacrificial Anode - Hot Water Heater Repair

Anode Rods, sometimes called sacrificial anodes, help to keep a water heater tank from rusting out.


To put it simply, corrosion will eat away the anode rod instead of the tank. That is why it is called a "sacrificial" anode.
When the anode rod has been eaten away, the tank will begin to rust very quickly.

Anodes rods are made of magnesium, aluminum, or a combination of aluminum/zinc. They screw into the top of the tank. Depending on the type or brand of water heater, some will screw into the hot water port and some hex head anodes have their own port.


Better water heaters will have two rods, one on the hot water port and one in its own port.

Sacrificial anodes are about the size of a quarter and are made onto a steel wire. When they have corroded away the steel wire will be exposed. If you can see several inches of the steel wire, the anode rod should be replaced.

How long they last depends on water temperature, water hardness,
water softener salt levels and if the water heater is flushed and cleaned on a regular basis.

As a general rule, check the rod every year after its two/three years old.

How to check and replace an anode rod page coming soon.


Low Hot Water Pressure

low pressure faucet

Sometimes, hot water heater repair does not involve working on the water heater at all. Problems can lead you to a dishwasher or faucet.

Low hot water pressure in your home is usually caused by sediment, calcium deposits, rust or other debris that has built-up inside the water heater tank.

Over time these particles will make their way into the hot water line and may clog the piping or the faucets.The tub/shower or bath sink is usually the first places you will have problems.

Sediment can also clog your dishwasher and washing machine. These two appliances have screens to keep debris out. Remove the water line where it attaches to the machine. You'll find the screens just inside the valve that you removed the water line from.

Calcium deposits look like tiny white rocks and can clog a faucet. If you have low pressure only at one faucet this should be the problem. The shut-off valve and supply line under a sink can also become clogged.

If your whole house has low hot water pressure you will need to check the pressure going into and out of the water heater. Also the hot water pipe leaving the tank could be clogged.
You can find a lot more information at this low hot water pressure guide.

Thanks for visiting hot water heater repair.


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